adaptive radiation

The evolution
of various divergent life-forms from a primitive and unspecialized ancestor.
As the original population spreads out from its center of origin to exploit
new habitats and food sources, new populations emerge, each adapted
to its particular environment. Eventually, these become sufficiently distinct
to be recognized as new species. Early placental
mammals, for example, gave rise to modern burrowing, climbing, flying, running,
and swimming forms.